Harlequins (20) 34
Try: Volley, Brown, Strettle, Abbott
Pens: Mehrtens (2)
Cons: Mehrtens (4)
London Irish (10) 17
Try: Flutey, Roche
Pens: Everitt
Cons: Everitt, Mordt
Andrew Mehrtens kicked two penalties and converted four tries on his first start since New Year's Day as Harlequins crushed London Irish.
After trading early penalties, tries in quick succession by Paul Volley and Mike Brown put Quins ahead, only for Irish's Rikki Flutey to pull one back.
Another double strike by Dave Strettle and Nick Abbott after the restart put the home side beyond the Exiles' grasp.
Slack defending let Kieran Roche pull a try back but it was too late too late.
Harlequins director of rugby Dean Richards:
"Our execution was outstanding and defensively we were strong.
"Andrew Mehrtens also played well, it's nice to see him back in contention. It makes a huge difference having someone with such experience in your ranks.
"We have a motivated group of guys at this club. We're turning the tables and a win was very important."
London Irish director of rugby Brian Smith: "We're scratching our heads to see what went wrong. The first-half tries were a kick in the teeth but we gave ourselves a shot at half-time.
"The period after the break was crucial and we got rolled over. We needed to
score first but we got blown away.
"They dominated the collision and fought for the ball on the floor."
Harlequins: Brown; Strettle, Deane, Abbott, Keogh; Mehrtens, Gomarsall; Jones, Fuga, Ross; Kohn, Evans; Vos, Volley (captain), Hala'Ufia.
Replacements: Hayter, Nebbett, Miall, Guest, Skinner, So'oialo, Williams.
London Irish: Armitage; Ojo, Mapusaua, Flutey; Tagicakibau; Everitt, Hodgson; Hatley, Russell, Lea'aetoa; Hudson, Casey (captain); Roche, Armitage, Murphy.
Replacements: Collins, Paice, Johnson, Magne, Danaher, Rees, Bishop.